Screw driver



Nov. 10, 1942. R. SIGNORELL] 2,301,590

SCREW DRIVER Filed Nov. 19, 1941 4 5 UI ENEJ L 5 El 3 a J a Attorney Patented Nov. 10, 1942 UNITED STATES PATENT OFFICE SCREW DRIVER Rudolph Signorelli, Lodi, N. J.

Application November 19, 1941, Serial No. 419,773

1 Claim.

My invention relates to improvements in screw drivers for use more particularly with screws having dovetailed kerfs, and the principal object in view is to provide a simply constructed, easily manipulated device of this character which may be quickly and positively interlocked with 'the kerf of a screw so that the screw cannot be lost, the screw driver cannot slip and the screw can be held and driven at any angle.

To the accomplishment of the above, and subordinate objects presently appearing, a. preferred embodiment of my invention has been illustrated in the accompanying drawing, set forth in detail in the succeeding description, and defined in the claim appended hereto.

In said drawing:

Figure l is a view in edge elevation of the preferred embodiment of my improved screw driver,

Figure 2 is a view in side elevation,

Figure 3 is a view similar to Figure 1 illustrating the driver applied,

Figure 4 is a view in end elevation of the screw, and

Figure 5 is a detail View in longitudinal section taken on the line 5-5 of Figure 2 and drawn to an enlarged scale.

'Referring to the drawing by numerals, the screw driver of my invention is designed to be used with a special screw, such as shown at A having a. dovetailed kerf B with undercut sides. The screw driver comprises a handle I, a flat shank 2 extending from one end of the handle and having an outer end 3 tapered edgewise, and a pair of elongated, strip-like, bit members 4 of resilient metal mounted upon opposite sides of the outer end portion of the shank 2 to extend endwise longitudinally of said shank and for endwise sliding movement on the shank.

The bit members 4 are provided with straight, outer working ends 5. A pair of transverse ribs 6 extend along the outer working ends 5 of said bit members, respectively, on the outer sides thereof for engaging the sides of the kerf B. lf'he ribs 8 are beveled, as at l, to lit the sides of the keri B and are provtded with rounded edges, as at 8, to facilitate entering the ribs 6 in the keri B. The mounting tor the bit members 4 cornprlses headed studs 8 extending laterally from the shank 2, and a longitudinal slot ill in each bit member through which said studs extend, the studs 9 and slot In providing for limited endwise udlngof the bit members 4 on the shank 2 and for extension of the working ends 5 of said bit members 4 beyond the outer end 3 of the shank 2 equidistantly.

In the use of the described screw driver, the bit members 4 are pulled outwardlv of the shank of the rounded edges 8, the ribs 6 may be entered in the kerf B with a snap action. As will be clear, when said working ends 5 are entered in the kerf B, the ribs 6 interlock with the sides of the kerf B. The handle I may next be manipulated to push the outer end 3 of said shank into the kerf B and between the ribs 6, in which position of said end of the shank 2 the ribs 6, or in other words, the working ends 5, are preventing from flexing toward each other and are thereby positively interlocked with the sides of said kerf B. To detach the bit members 4, it is merely necessary to exert the requisite pull on the handle I to withdraw the outer end 3 of the shank I from the kerf B and from between the working ends 5 of the bit members 4 until one of the studs 9 engages the inner ends of the slots 10, at which point the shank 2 will withdraw the working ends 5 of said bit members 4 from the kerf B.

The foregoing will, it is believed, sufiice to impart a clear understanding of my invention without further explanation.

Maniiestly, the invention, as described, is susceptible oi modification without departing from the inventive concept, and right is herem reserved to .such modifications as fall within the scope of the appended claim.

What I claim is:

A screw driver for use with a screw having a dovetailed kerf with undercut sides comprising a handle, a fiat shank extending from one end of the handle and having a transversely straight outer end, and a pair of elongated strip-like bit members of resilient metal mounted upon opp0 site sides of said outer end of the shank to extend endwise longitudinally of said shank in spaced apart parallel relation, said bit members having straight outer working ends for entering the kerf oithe screw, and a pair of transverse ,ribs extending along the working ends of the bits,

respectively, for engaging and interlocking with the sides of the kerf. the mounting for said bit members providing for relative endwise sliding movement of said members and said shank whereby the latter may be slid into the kerf oi the screw between said working ends of said bit members to maintain said ribs interlocked with said sides of said kerf, said ribs being beveled to fit the sides of said keri and having rounded outer side edges for facilitating entering said working ends in said kerf.

RUDOLPH SIGNORELLI. 

